I am currently trying to free up a tape unit within my removable storage tape drive. However I continue to get the Data error (cyclic redundancy check) error. Any suggestions as to what this means or how to avoid getting this error?

I am receiving the error from Windows Backup utility on a windows 2003 server. I am using 4mm DDS4 tapes 20GB/40GB on a Quantum DAT Tape Drive.

Is it one tape or multiple tapes? If it's only one tape then it's probably bad. If it's multiple tapes then it may mean that the drive needs cleaning. It may also mean that the drive itself is failing.